We have developed an omnidirectional gamma-ray imaging Compton camera for environmental monitoring at low levels of radiation. The camera consisted of only six CsI(Tl) scintillator cubes of 3.5 cm, each of which was readout by super-bialkali photo-multiplier tubes (PMTs). Our camera enables the visualization of the position of gamma-ray sources in all directions (>4π sr) over a wide energy range between 300 and 1400 keV. The angular resolution (σ) was found to be >11°, which was realized using an image-sharpening technique. A high detection efficiency of 18 cps/(µSv/h) for 511 keV (1.6 cps/MBq at 1 m) was achieved, indicating the capability of this camera to visualize hotspots in areas with lowradiation-level contamination from the order of µSv/h to natural background levels. Our proposed technique can be easily used as a low-radiationlevel imaging monitor in radiation control areas, such as medical and accelerator facilities.

Chemotherapy-induced neutropenia (CIN) has been associated with a risk of infections and chemotherapy dose reductions and delays. The chemotherapy regimen remains one of the primary determinants of the risk of neutropenia, with some regimens being more myelotoxic than others. Although a number of clinical trials have currently highlighted the risk of CIN with each chemotherapy regimen, only a few ones have comprehensively examined the risk associated with all chemotherapeutic agents. Therefore, this study aimed to investigate the risk factors and characteristics of CIN caused by each neoplastic agent using data from the large voluntary reporting Food and Drug Administration Adverse Event Reporting System database. Initially, univariate analysis showed that an age ≥ 65 years, the female sex, and treatment with chemotherapeutic agents were factors that caused CIN. Then, cluster and component analyses showed that cytotoxic agents (i.e., alkylating agents, antimetabolic agents, antineoplastic antibiotics, platinating agents, and plant-derived alkaloids) were associated with infection following neutropenia. This comprehensive analysis comparing CIN risk suggests that elderly or underweight patients treated with cytotoxic drugs require particularly careful monitoring.

This proof-of-concept study shows that [F-18]FLT-PET/CT is a sensitive method for detecting PM in GC, and paves the way for future studies investigating the clinical utility of this approach for the detection of clinically non-evident PM in GC. Advances in knowledge: This proof-of-concept study found that [F-18]FLT-PET/CT is a sensitive method for detecting peritoneal metastases in GC.

Irinotecan (CPT-11) is widely used for the treatment of unresectable colorectal cancer in combination with fluoropyrimidines, such as 5-fluorouracil and S-1. Diarrhea is one of the adverse effects associated with CPT-11 and frequently reported by patients treated with CPT-11-containing regimens combined with oral fluoropyrimidines. However, the mechanisms involved in this process, as well as whether fluctuations in the frequency and differences in the onset time of diarrhea with each CPT-11-containing regimen are caused by drug interactions remain unclear. Therefore, we examined the incidence of diarrhea caused by each CPT-11-containing regimen in patients with colorectal cancer using data from the large voluntary reporting Japanese Adverse Drug Event Report (JADER) database. Firstly, we searched for suspected drugs related to the occurrence of diarrhea using reported odds ratio and calculated the signal score to assess drug–drug interactions. Subsequently, we conducted a time-to-onset analysis using Weibull distribution. The results showed that the combination of CPT-11 with S-1 increased the frequency of diarrhea due to a pharmacological interaction but delayed its onset. The present results may contribute to the appropriate management of drug-induced adverse effects by healthcare professionals.